Method of producing dies for extrusion molding of honeycomb structure bodies
Ceramic honeycomb structure bodies are produced by using a die composed of ceramic batch supplying holes through which a ceramic batch is supplied and slit grooves through which the ceramic batch is extruded and shaped in a honeycomb structure shape. In a method of producing such a die, hardening is performed onto at least a slit groove formation surface of a die member in order to form a hardening treated film on the slit groove formation surface of the die member. After the completion of the hardening process, plural slit grooves are formed in the slit groove formation surface of the die member. A hardness of the hardening treated film of the die member is not less than 1.5 times of a hardness of the die member.
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This application is related to and claims priority from Japanese Patent Application No. 2006-187048 filed on Jul. 6, 2006, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a method of producing dies for use of performing extrusion molding for extruding honeycomb structure bodies in a lattice (or honeycomb) structure.
2. Description of the Related Art
Honeycomb structure bodies made of ceramic are used as exhaust gas purifying filter for purifying particulate matters (PM) in an exhaust gas emitted form an internal combustion engine such as a diesel engine of a vehicle. Such honeycomb structure bodies are produced by extruding ceramic batch of ceramic raw material through a honeycomb structure body extruding die (hereinafter, referred to as “die” in short).
One of various types of dies is composed of a die member in which batch supplying holes and slit grooves are formed. Ceramic batch of ceramic raw material is supplied through the batch supplying holes. The slit grooves are formed in a lattice (or honeycomb) structure and join to the batch supplying holes. Through the slit grooves, the ceramic batch of ceramic raw material is shaped into a honeycomb structure body in a lattice shape or a honeycomb structure shape. The repetition use of the die during the extrusion molding causes abrasion of the die because of contacting the ceramic batch to the die many times, and therefore raises its deterioration and of decreasing its dimensional accuracy.
In order to solve such a problem of the related-art techniques, Japanese patent laid open publication No. JP H5-269719 has proposed a method of coating the entire surface of a die having a plurality of batch supplying holes and slit grooves with abrasion proof material by using chemical vapor deposition (CVD) manner so as to enhance the abrasion proof performance of the die. However, it is in general difficult to form a uniform abrasion proof material onto the surface of the batch supplying holes and slit grooves in the die which have a complicated configuration. The related art techniques hardly keep the abrasion proof performance of the die for a long period of time. There is therefore a possibility of decreasing the dimensional accuracy of honeycomb structure bodies produced by the die which is made by the conventional manner. For this reason, there is a strong demand for producing dies of superior durability and abrasion proof performance, for use of performing the extrusion molding for producing ceramic honeycomb bodies.
SUMMARY OF THE INVENTIONIt is an object of the present invention to provide a method of easily and certainly producing dies having superior durability and abrasion proof performance for use of performing the extrusion molding of extruding honeycomb structure bodies.
To achieve the above purpose, the present invention provides a method of producing dies for use of performing extrusion molding of honeycomb structure bodies. Each die has batch supply holes and slit grooves formed in a lattice shape. Those slit grooves are joined to the batch supply holes. The slit grooves are capable of shaping the ceramic batch to a honeycomb structure body of a honeycomb shape. The method has steps of preparing a die member, hardening at least a slit groove formation surface of the die member in order to form a hardening treated film on the slit groove formation surface, and forming slit grooves in the slit groove formation surface of the die member. A hardness of the hardening treated film is not less than 1.5 times of the hardness of the die member.
In the method of producing dies for use of producing honeycomb structure bodies, the slit grooves are formed in the slit groove formation surface of the die member after the completion of the hardening process performed for at least the slit groove formation surface.
On the contrary, in related art techniques, the hardening process is performed to the surface of a complicated shape in which the slit grooves have already been formed.
That is, according to the method of the present invention, the hardening process is performed to the slit groove formation surface of a simple shape before the completion of the slit groove formation process. It is thereby possible to easily perform the hardening process in order to enhance the durability and abrasion proof performance of the die. In addition, the method according to the present invention provides the hardening treated film of a uniform thickness formed on the slit groove formation surface of the die member.
Further, the hardening process performs the hardening to at least the slit groove formation surface in order to form the hardening treated film thereon. The slit groove formation surface of the die produced by the method becomes a surface in which the plural slit grooves are formed, through which ceramic batch of raw material is extruded during the manufacturing honeycomb structure bodies. That is, the slit groove formation surface is the important surface to strongly influence the quality in shape of and the dimensional accuracy of the honeycomb structure bodies to be manufactured, because the slit groove formation surface is contacted with the ceramic batch of raw material many times in the manufacturing of the ceramic honeycomb structure bodies and causes excessive wear.
The method according to the present invention performs the hardening to the slit groove formation surface in order to make the hardening treated surface of a uniform thickness on the slit groove formation surface. Such a process sequence in the method according to the present invention can provide the dies having the superior durability and abrasion proof performance. It is also possible to keep the quality in shape of and the dimensional accuracy of the honeycomb structure bodies produced by using the die which is produced by the method according to the present invention.
In particular, the hardness of the hardening treated film is not less than 1.5 times of the hardness of the die member. The presence of the hardening treated film can enhance the durability and abrasion proof performance of the die produced.
According to the method of producing the dies, it is possible to easily and certainly produce the dies of superior durability and abrasion proof performance.
By the way, the hardness of the hardening treated film which is less than 1.5 times of the hardness of the die member causes a possibility of not providing the durability and abrasion proof performance of the die with adequate efficiency.
It is possible to perform slicing process manner in the slit groove formation process of forming the slit grooves. Such a slicing process manner using a thin cutter with diamond particles processes the slit groove formation surface in the die member.
It is further possible to use, as the die member, one of metals such as SKH (high speed steel), SKD (alloy tool steel), Stainless, Aluminum alloy, Titanium, Inconel®, HASTELLOY®, Stellite, Cemented carbide alloy, cermet, and related materials. The use of such a metal can easily and certainly form the hardening treated film on the die member.
It is preferred to perform the hardening process by one of PVD, CVD, DLC, electroplating, and electroless plating. Those manners can form the hardening treated film with high accuracy, and enable the die to certainly enhance its durability and abrasion proof performance. The present invention is not limited by using those manners, for example, it is possible to combine both the PVD and CVD processes, and also possible to combine a plurality of the hardening processes.
In particular, the PVD process can provide the hardening treated film with superior high-accuracy when compared with other hardening processes. In addition, because the PVD process can form a thicker film, the PVD process can form the hardening treated film with high efficiency.
The use of CVD process can enhance the adhesive capability of the hardening treated film to the die member. It is therefore possible to enhance the durability of the hardening treated film of the die.
The use of DLC (diamond like carbon) process can produce a DLC film of an extreme hardness. It is thereby possible to enhance the durability of the hardening treated film by performing DLC process.
It is preferred the hardness of the die member is not less than Hv 500. Because it is difficult to adequately keep the hardness of the die member when it is less than Hv500, there is a possibility of causing deformation of the die member. Such a deformation causes damage and separation of the hardening treated film from the die member. Hv500 or more corresponds approximately not less than 40 HRC.
It is therefore preferred that the hardness of the die member is within a range of Hv 500 to 760.
This case can adequately keep the hardness of the die member. It is thereby possible to suppress deformation of the die member and to form the batch supply holes and the slit grooves without causing any trouble. The hardness within a range of Hv500 to 760 corresponds approximately a range of 40 to 70 HRC.
It is preferred that the hardness of the hardening treated film is not less than Hv750.
Because the hardness of the hardening treated film of less than Hv750 does not adequately keep the hardness of the hardening treated film, there is a possibility of not increasing the durability and abrasion proof performance of the die.
It is therefore preferred that the hardness of the hardening treated film is not less than Hv1500. This case can adequately keep the hardness of the hardening treated film and further enhance the durability and abrasion proof performance of the die.
It is preferred that the thickness of the hardening treated film is not more than 1/10 times of a depth of each slit groove. When the thickness of the hardening treated film exceeds 1/10 times of a depth of each slit groove, because the pressure while extruding the ceramic batch of the raw material becomes high, there is a possibility of decreasing the formation speed and of breaking the die.
It is preferred that the thickness of the hardening treated film is not more than 0.5 mm. When the thickness of the hardening treated film is more than 0.5 mm (exceeds 0.5 mm), there is a possibility of decreasing the accuracy of forming the hardening treated film, and a possibility of decreasing the variation of the thickness of the honeycomb structure bodies produced by using the die. There is further a possibility of abnormally growing catalysts of the hardening treated film. This causes the separation of the hardening treated film from the die member.
A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:
Hereinafter, various embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the various embodiments, like reference characters or numerals designate like or equivalent component parts throughout the several diagrams.
First EmbodimentA description will now be given of a method of producing dies for use of extruding ceramic batch in order to produce honeycomb structure bodies according to a first embodiment of the present invention.
The honeycomb structure body shaping die 1 (hereinafter, referred to as “the die 1” in short) shown in
In the method of producing the die 1 according to the first embodiment of the present invention, a slit groove formation process of making the slit grooves 13 is performed after the completion of a hardening process which forms a hardening treated film 2 on a slit groove formation surface 130 of the die member 11. The hardness of the hardening treated film 2 is not less than 1.5 times of that of the die member 11.
A description will now be given of the hardening process and the slit groove formation process in the method according to the first embodiment.
<Preparation Step>As shown in
A description will now be given of the hardening process performed by the CVD apparatus in detail.
As shown in
A gas supply inlet 441 is formed at a bottom part 422 of the reaction furnace 42. Through the gas supply inlet 441 and gas supply pipes 442, reaction gases are introduced from a gas supply apparatus 46 into the reaction furnace 42. The gas supply apparatus 46 is placed at the outside of the CVD apparatus 4. Thus, the CVD apparatus 4 has the configuration of introducing the reaction gases from the gas supply apparatus 46 into the reaction furnace 42. The method of the first embodiment uses TiCl4, H2, Ar, CH4 and N2 as the reaction gases.
As shown in
In the hardening process, the CVD process is performed in the CVD apparatus 4. At first, masking is performed on the batch supplying hole formation surface 120 of the die member 11. In a concrete example, as shown in
Next, as shown in
As shown in
The reaction furnace 42 is then cooled after the completion of the chemical reaction. The CVD jig 321 is taken out from the reaction furnace 42 and the die member 11 is released from the CVD jig 321.
As shown in
Next, as shown in
The honeycomb structure body shaping die 1 is produced by the above processes.
As shown in
As shown in
Next, a description will now be given of the action and effects of the method and the die produced by the method according to the first embodiment of the present invention. In the method of the first embodiment described above, the slit groove formation process of making the slit grooves 13 is performed after the hardening process. That is, before forming or processing the slit grooves 13, the hardening process is performed in order that the hardening treated film 2 is formed on the slit groove formation surface 130. Following, the slit grooves 13 are formed in the slit groove formation surface 130 of a flat shape which has been processed by the hardening process.
Therefore, in the method of producing the die according to the first embodiment, the hardening process is performed for the slit groove formation surface 130 of a plane shape before performing the slit groove formation process. Thereby, the method of the first embodiment can easily perform the hardening process with high accuracy in order to increase and enhance the durability and abrasion proof performance of the die 1 as the product. Further, the method of the first embodiment can uniformly form the hardening treated film 2 on the slit groove formation surface 130.
On the contrary, in related-art techniques, a hardening process is performed to the surface of a die member having a complicated shape in which slit grooves have already been formed.
In the method of the first embodiment, the hardening process is firstly performed for the slit groove formation surface 130, and the hardening treated film 2 is formed on the slit groove formation surface 130 of the die member 11.
On producing the honeycomb structure bodies, the slit groove formation surface 130 in the die 1 as the product of the method of the first embodiment is the surface having the plural slit grooves 13 through which the ceramic batch of ceramic raw material is extruded. In other words, the slit groove formation surface 130 is the important surface for keeping the high quality in shape of and the accuracy in dimension of the honeycomb structure bodies to be produced. In addition, the slit groove formation surface 130 is rapidly worn away since it has been used with ceramic batch so frequently. The method of the first embodiment performs the hardening process to the slit groove formation surface 130 and makes the hardening treated film 2 of a uniform thickness on the slit groove formation surface 130. This can efficiently increase and enhance the durability and abrasion proof performance of the die 1 as the product. The method of the first embodiment can keep the quality in shape of and the accuracy in dimension of the honeycomb structure body produced.
Further, the method of the first embodiment provides the hardening treated film 2 formed on the slit groove formation surface 130, where the hardness of the hardening treated film 2 is not less than 1.5 times of that of the die member 11. The formation of the hardening treated film 2 can improve the durability and abrasion proof performance of the die 1 produced.
The method of the first embodiment uses CVD process as the hardening process. Such a CVD process can enhance the degree of the adhesion of the hardening treated film 2 onto the slit groove formation surface 130. This can provide the superior durability of the hardening treated film 2 in the die 1.
Still further, because the hardness of the hardening treated film 2 is not less than Hv1500, it is thereby possible to adequately keep the hardness of the hardening treated film 2 and to further enhance the durability and abrasion proof performance of the die 1.
According to the method of the first embodiment described above, it is possible to easily perform the hardening process with high accuracy in order to enhance the durability and abrasion proof performance of the die 1 for use of extruding ceramic batch of raw material for producing honeycomb structure bodies. Still further, the use of the die 1 in the extrusion molding process can provide the honeycomb structure bodies having a superior durability and abrasion proof performance.
In the hardening process in the method of the first embodiment, as shown in
In addition, it is possible to process the plural batch supplying holes 12 after removing the hardening treated film 2 from the batch supplying hole formation surface 120 by performing surface grinding.
Although the plural batch supplying holes 12 are formed after the hardening process, it is acceptable to form the plural batch supplying holes 12 before performing the hardening process. That is, in the method of the first embodiment, it is possible to perform the hardening process and the slit groove formation process after the preparation process and the batch supplying holes formation process. In this case, like the manner of the first embodiment, it is possible to provide the die 1 having the superior durability and abrasion proof performance.
Further, although the hardening treated film 2 is formed on the batch supplying hole formation surface 120 having the plural batch supplying holes 12 when no masking is performed in the hardening process, it is possible to produce the die 1 with high quality in shape and with high dimensional accuracy, and with superior durability and abrasion proof performance.
Second EmbodimentIn the method of producing the die 1 for use of performing the extrusion molding of a ceramic batch for producing honeycomb structure bodies according to the second embodiment of the present invention, a physical vapor deposition (PVD) process is performed as the hardening process instead of the CVD process used in the first embodiment. In the following explanation of the method of the second embodiment, the PVD process is performed on the slit groove formation surface 130 of the die member 11. The PVD process is performed by a PVD apparatus 5 shown in
A description will now be given of the PVD process as the hardening process in the method according to the second embodiment.
As shown in
As shown in
A gas supply inlet 551 and a gas exhaust outlet 552 are formed at a ceiling part 513 of the reactor 51. The reaction gases are introduced through into the reactor 51 from gas supply apparatus (not shown), and the residual reaction gases are exhausted to the outside of the reactor 51 through the gas exhaust outlet 552. A vacuum pump (not shown) is mounted on the reactor 51.
In the hardening process in the method according to the second embodiment, namely, as the PVD process performed by the PVD apparatus 5 of the above configuration, a masking is firstly performed on the batch supplying hole formation surface 120 in the die member 11.
The die member 11 and the masking plate 31 are tightly fastened and fixed by the PVD jig 322. The masking is then performed on the batch supplying hole formation surface 120 of the die member 11.
Following, as shown in
The reactor 51 is then vacuumed to 1×10−6 Torr by the vacuum pump (not shown) and heated at 500° C. under the pressure of 1×10−6 Torr. In this condition, the reaction gas N2 is supplied into the reactor 51 through the gas supply inlet 551.
Next, as shown in
The speed of those ions is accelerated by applying the bias voltage from the bias power supply to the PVD jig 321 through the turn table 54.
Those flying ions and reaction gas particles (N2) as film material (CrN and TiN used in the second embodiment) collide with the slit groove formation surface 130 of the die member 11 and are accumulated as a thin film on the slit groove formation surface 130. In the second embodiment, because the above process is performed while rotating the turn table 54, it is possible to form the thin film of a uniform thickness on the slit groove formation surface 130 of the die member 11.
Following, the reactor 51 is cooled to an atmosphere pressure condition. The PVD jig 322 is taken out from the reactor 51. The die member 11 is released from the PVD jig 322.
In the second embodiment, the PVD process is further performed again using the metal target 52 made of Titanium (Ti) after the PVD process using the metal target 52 made of chromium (Cr). It is thereby possible to obtain the die member 11 in which the hardening treated film 2 is formed on the slit groove formation surface 130. The hardening treated film 2 has a double layer configuration made of a CrN layer and a TiN layer.
Other processes in the method according to the second embodiment are the same as those in the method of the first embodiment. Therefore the explanation of those same processes is omitted here.
The die 1 for use of performing the extrusion molding for producing the honeycomb structure bodies is produced by the method described above.
The die 1 according to the second embodiment has the hardening treated film 2 formed on the slit groove formation surface 130, like the configuration (shown in
The hardness of the hardening treated film 2 in the die 1 produced by the method of the second embodiment is Hv2000 which is approximately four times of that of the die member 11. The thickness “S” of the hardening treated film 2 is 1.8 μm, and the depth “D” of the hardening treated film 2 is 1/10 times of the depth (=5 mm) of the slit groove 13.
As shown in
The method of producing the die according to the second embodiment can produce the die of a superior durability and abrasion proof performance, like the method according to the second embodiment.
The method of the second embodiment performs the PVD process. In general, the PVD process produces a film with extremely high accuracy, and it is thereby possible to form the hardening treated film 2 with more high accuracy. Because the PVD process can provide a thick film, it is possible to efficiently form the hardening treated film 2.
The method of the second embodiment has other effects which are the same as those of the method according to the first embodiment.
In the method of the second embodiment, as shown in
In the method of the second embodiment, the plural batch supplying holes 12 are formed after the hardening process. However, it is possible to form the plural batch supplying holes 12 in advance before performing the hardening process. That is, the method of the second embodiment can perform the sequence of the hardening process and the slit groove formation process after the preparing process and the batch supplying hole formation process in order.
Third EmbodimentThe method according to the third embodiment of producing the die 1 for use of performing the extrusion molding process of producing honeycomb structure bodies performs the hardening process by both the CVD process and the PVD process.
In the third embodiment, the CVD process is performed on the slit groove formation surface 130, and the PVD process is then processed on the slit groove formation surface 130. The CVD process is performed by the same sequence of the CVD process in the first embodiment, and the PVD process is performed by the same sequence of the PVD process in the second embodiment.
The remaining processes other than the CVD process and the PVD process are the same as those in the method of the second embodiment. Therefore the explanation of those same processes in the method of the third embodiment is omitted here.
The die 1 for use of performing the extrusion molding of the honeycomb structure bodies produced by the method of the second embodiment, as shown in
The die produced by the method of the third embodiment has the action and effects which are the same of those of the die produced by the method of the first embodiment.
Fourth EmbodimentThe fourth embodiment provides the evaluation results of life of various types of the dies (Samples E1 to E3) produced by the first to third embodiments according to the present invention and the die (as comparison Sample C) produced by a conventional manner. That is, in the evaluation in life, plural honeycomb structure bodies were produced repeatedly by using the following samples:
Sample E1 (die) produced by the method according to the first embodiment using CVD process;
Sample E2 (die) produced by the method according to the second embodiment using PVD process;
Sample E3 (die) produced by the method according to the third embodiment using both CVD process and PVD process; and
Comparison sample C (comparison die) produced by a related art manner without CVD process and PVD process.
An initial width of the slit groove 13 in each sample (die) is 140 mm.
Next, a description will now be given of the evaluation manner of evaluating the samples E1 to E3 and the comparison sample C.
Ceramic batch including cordierite ceramic raw material was extruded through the samples E1 to E3 (samples E1 to E3). Each honeycomb structure body produced by the samples has a cylindrical shape whose diameter is 100.0 mm and whose length is 90.0 mm. The production of each types of the honeycomb structure body was repeated until the useful life of the die, namely, until the width of the slit groove 13 reaches 150 μm or more.
The comparison sample C having the same configuration of the samples E1 to E3 produced by the related-art manner was evaluated by the same manner described above.
In the evaluation, the number of the honeycomb structure bodies produced by using each sample was counted until the useful life of each die was given out.
As shown in
The sample E2 of the die 1 produced by the method of the second embodiment using the PVD process has the improved productivity of the honeycomb structure bodies which is twice of that of the sample C which was produced without any CVD process.
The sample E3 of the die 1 produced by the method of the third embodiment using the combination of the CVD process, the PVD process, and the hardening process has the improved productivity of the honeycomb structure bodies which is three times of that of the sample C produced without the CVD and PVD processes.
Accordingly, it can be understood that the dies produced by the methods according to the first to third embodiments of the present invention has superior durability and superior abrasion proof performance and has an increased useful life.
The method of producing the dies according to the present invention described above uses alloy tool steel (SKD) as the die member. It is possible to use, as the die member, one of metals such as SKH (high speed steel), Stainless, Aluminum alloy, Titanium, Inconel®, HASTELLOY®, Stellite, Cemented carbide alloy, cermet, and related materials, instead of SKD. The use of such a metal can easily and certainly form the hardening treated film on the die member.
Further, the method of producing the dies according to the present invention described above uses CVD, PVD or a combination of CVD and PVD in the hardening process. It is possible to perform the hardening process by using one of DLC, electroplating and electroless plating. Such manners can form the hardening treated film with high accuracy, and it is possible to certainly enhance the durability and abrasion proof performance of the die produced by performing such manners. It is possible to use another manner and further possible to combine a plurality of those manners.
While specific embodiments of the present invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limited to the scope of the present invention which is to be given the full breadth of the following claims and all equivalent thereof.
Claims
1. A method of producing dies for performing extrusion molding of honeycomb structure bodies, each die having batch supply holes and slit grooves formed in a lattice shape joined to the batch supply holes, and the slit grooves being capable of shaping the ceramic batch to a honeycomb structure body of a honeycomb shape, the method comprising steps of:
- preparing a die member;
- hardening at least a slit groove formation surface of the die member in order to form a hardening treated film on the slit groove formation surface, where a hardness of the hardening treated film is not less than 1.5 times of the hardness of the die member; and
- forming slit grooved in the slit groove formation surface of the die member.
2. The method according to claim 1, wherein the hardening process is performed by one of PVD, CVD, DLC, electroplating, and electroless plating.
3. The method according to claim 1, wherein the method uses the die member whose hardness is not less than Hv 500.
4. The method according to claim 1, wherein the method uses the die member whose hardness is within a range of Hv 500 to 760.
5. The method according to claim 1, wherein the hardening process forms the hardening treated film whose hardness is not less than Hv 750.
6. The method according to claim 1, wherein the hardening process forms the hardening treated film whose hardness is not less than Hv 1500.
7. The method according to claim 1, wherein the hardening process forms the hardening treated film whose thickness is not more than 1/10 times of a depth of each slit groove.
8. The method according to claim 1, wherein the hardening process forms the hardening treated film whose thickness is not more than 0.5 mm.
9. The method according to claim 1, wherein the die member is made of one of SKH (high speed steel), SKD (alloy tool steel), Stainless, Aluminum alloy, Titanium, Inconel®, HASTELLOY®, Stellite, and Cemented carbide alloy, cermet.
10. The method according to claim 2, wherein the die member is made of one of SKH (high speed steel), SKD (alloy tool steel), Stainless, Aluminum alloy, Titanium, Inconel®, HASTELLOY®, Stellite, and Cemented carbide alloy, cermet.
11. The method according to claim 9, wherein the method uses the die member whose hardness is not less than Hv 500.
12. The method according to claim 9, wherein the method uses the die member whose hardness is within a range of Hv 500 to 760.
13. The method according to claim 9, wherein the hardening process forms the hardening treated film whose hardness is not less than Hv 750.
14. The method according to claim 9, wherein the hardening process forms the hardening treated film whose hardness is not less than Hv 1500.
15. The method according to claim 9, wherein the hardening process forms the hardening treated film whose thickness is not more than 1/10 times of a depth of each slit groove.
16. The method according to claim 9, wherein the hardening process forms the hardening treated film whose thickness is not more than 0.5 mm.
Type: Application
Filed: Jun 26, 2007
Publication Date: Jan 10, 2008
Applicant: DENSO CORPORATION (Kariya-city)
Inventor: Hitoshi Kanmura (Mie-ken)
Application Number: 11/819,213